[Wrf-users] Anyone deals with cloud simulations in WRF

Mike Tod clivarclivar at yahoo.com
Wed Feb 4 19:04:10 MST 2009

Hi there,

I have a question on the WRF simulation of cloud amount.

In the output, there is a variable "CLDFRA" (cloud fraction),
which are either 0 or 1. My question is
how to calculate the cloud amount for the low cloud?
For example, we can use the cloud fractions below 800hPa 
(or 680hPa as ISCCP used).
Do we just do the average from the surface layer to the 800 hPa layer?
For example, from surface to 800hPa, we have totally 15 layers.
Then we count the layers with CLDFRA=1 for one point at one time is 6,
and CLDFRA=0 is 9, then we calculate the "true" cloud fraction is

I am not sure about this method, which seems toooo simple.
Do you have any suggestions on this?

Thanks a lot!


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